AERODYNAMIC ANALYSIS OF UNMANNED AIR VEHICLE (UAV) WITH

DIFFRENT WING CONFIGURATION

 Projected by : Guided by :Akash patel Arpit patelKedar thaker Dhruvin shah

 ABSTRACT

The aim of this project is to do analysis over wing by means of three different types of wing which are joined wing, hybrid wing and tailless wing for UNMANNED AIR VEHICLE (UAV) to discover what happens in aerodynamic point of view. We create three different wing models using CATIA. Then after to learn the basic aerodynamic concepts and Computational Fluid Dynamic (CFD) analysis is performed on CAD model. To find out its particular application in different way in aerodynamic point of view for UAV with the help of determination of coefficient of lift, coefficient of drag and generation of vortices at cruising speed and different angle of attack (AOA). Finally we compare these three wing configurations to select one which is most efficient and usable for UAV aerodynamically.

Aerodynamic analysis of unmanned air vehicle (UAV) with different wing configuration

Abstract

Introduction

Literature review

Modelling of hybrid wing, joined wing and tailless wing using CATIA

Mesh generation

Mesh check

Analysis

Result

Conclusions

References

Yes

Yes

Comparison

No No

No

LITERATURE REVIEW

Our project based three different wing configuration which are categorized joined wing, hybrid wing and tailless with blended body which follows three different cases of different research paper.

Joined wing: We follow Research paper of Gyeongsang National University, University of Alabama in Huntsville, Huntsville, AL, USA, University of Michigan, Ann Arbor, Michigan, Massachusetts Institute of Technology, Cambridge, Massachusetts, Technical University of Sofia, Aviations Engines Department National Aviation University Kyiv, Ukraine, U.S. Air Force Institute of Technology, Wright–Patterson Air Force Base, Ohio for jointed wing for UAV.

LITERATURE REVIEW

Specification Main wing Tail wing

Span (m) 5 5

Sweep angle (˚) 15 -15

Dihedral angle (˚) 2.5 -5.5

Incidence angle (˚) 2 2

Root chord length (m) 0.48 0.2

Tip chord length (m) 0.24 0.2

Main wing airfoil Tail wing airfoil

NACA 4415 NACA 0012

LITERATURE REVIEW

Hybrid wing: We follow research paper of Department of Mechanical Engineering, PES Institute of Technology, Bangalore

This wing is combination of rectangular wing and Trapezoidal wing configuration.

Specification Value Wing span (m) 1.40

Root (m) 0.24

Tip (m) 0.17

Wing area (m) 0.28

Aspect ratio 6.90

Main wing airfoil NACA 4412

LITERATURE REVIEW

Tailless wing: We follow research paper of Alexander S. Goodman Marques Aviation Ltd, USA , Northwestern Polytechnical University, Xi’an 710072, China, West Virginia University, Morgantown, WV, Unmanned Vehicle University, Southport, UK, School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Australia, Department of Aeronautics and Astronautics, Institute of Space Technology, Islamabad, Pakistan , Department of Mechanical Engineering, HITEC University, Taxila Education City, Pakistan for tailless wing with blended body wing configuration.

The design of tailless wing quite complex compare to others.

LITERATURE REVIEWTailless wing configuration with winglet which functioning to help to

reduces vortices at wing tip.

Specification Value

Wing span (m) 2.6

Wing area (m2) 0.76

Aspect ratio 8.89

Root chord(m) 0.4

Tip chord (m) 0.185

Taper ratio 0.46

Sweep angle (˚) 15

Main wing airfoil Fauvel 12%

LITERATURE REVIEW

All these research papers in which we studied about Mach number, Viscosity, Reynolds number, Aerodynamic forces, Lift coefficient, Drag coefficient, Bernoulli’s principle, Wingtip vortex development, Boundary layer, Flow separation etc.

We taking different angle of attack like 0˚,4˚,8˚,12˚ with different speed to compare these three wing and find out its coefficient of lift, coefficient of drag and generation of vortices at different Mach number.

The numerical simulation we compare and find out the optimized results one of these wing configuration with help of chart and to find out its application aerodynamically for UAV

INTRODUCTION

In this project, Computational Fluids dynamics analysis of different winglets with different wing configurations perform and to understand the aerodynamics concepts.

Aerodynamics from the union of two Greek words: Eros, which means air, and dynamics, meaning power. Thus, aerodynamics is the study of forces and movements that occur in objects through the air.

The branch of fluid mechanics that studies the actions on the solid objects when there is relative motion between them and the fluid that bathes them.

There are different classifications for aerodynamic problems.

INTRODUCTION

Incompressible flow, when the air velocity is lower than Mach 0.3Compressible flow, the air velocity is higher than Mach 0.3Subsonic, flow velocity is always lower than sound velocity, M=1. All commercial aircraft are flying below M=1. Transonic, flow velocity is in between 0.8 to 1.2 MachSupersonic, flow velocity is higher than M=1 Hypersonic, when the flow velocity is much higher than sound

velocity, about M>6

INTRODUCTION

Mach number:The Mach number is a number that is used as speed reference. The

Mach number is used to assess whether the phenomena due to the change in air density compressibility have or not very important, that is to say, if they are negligible.

We define the Mach number as shown in equation and we see that when the fluid velocity is equal to the speed of sound we have M = 1.

M = v/cFlight speed/speed of sound

INTRODUCTION

Viscosity is a measure of the resistance of a fluid which is being deformed by either shear stress or extensional stress. In other words, Viscosity is a measure of a fluid's resistance to flow. It describes the internal friction of a moving fluid. A fluid with large viscosity resists motion because its molecular make up gives it a lot of internal friction.

In general, in any flow, layers move at different velocities and the fluid's viscosity arises from the shear stress between the layers that ultimately oppose any applied force.

INTRODUCTION

The Reynolds number relates the density, viscosity, speed and size of a typical flow in a dimension less expression, which is involved in many fluid dynamics problems. This dimensionless number or combination appears in many cases related to the fact that laminar flow can be seen (small Reynolds number) or turbulent (Reynolds number largest). From a mathematical point of view the Reynolds number of a problem or situation is defined by the following equation:

Re = ρVL / µ

INTRODUCTIONAerodynamic forces are those displayed by the fact of having a body moves at

speed immersed in a fluid. There are the following forces in an aircraft: -Weight, although not strictly an aerodynamic force is always present, and will determine the lift we need to keep the plane in the air. It is a force that is always directed toward the center of the earth. The magnitude of the weight depends on the mass of all the airplane parts, plus the amount of fuel, plus any payload on board -Lift, the lift is the force perpendicular to the direction of the free stream. To overcome the weight force, airplanes generate an opposing force called lift. The magnitude of the lift depends on several factors including the shape, size, and velocity of aircraft. -Drag, the drag is defined as the force component in the direction of the free stream. As the airplane moves through the air, there is another aerodynamic force present. The air resists the motion of the aircraft and the resistance force is called drag. Like lift, there are many factors that affect the magnitude of the drag force -Thrust, is not an aerodynamic force. To overcome drag, airplanes use a propulsion system to generate a force called thrust.

INTRODUCTION

When there is a fluid moves through the wing, forcing air particles to narrow at the upper surface of the wing, while the air particles that travel at the lower surface of the wing are expanded.

Therefore, the flow velocity is increased at the upper surface and the pressure goes down. On the other hand, the flow velocity drops at the lower surface and the pressure grows. The pressure difference between lower and upper surface generates an aerodynamic force called lift. When a stream of air moves over a profile produces a force called aerodynamics. This force is usually decomposed into two components: Lift and Drag. The lift, L, is the component perpendicular to the free flow of air, and L is defined by the following the equation:

L = ½ ρ V² S Cl

INTRODUCTION

The drag coefficient can be computed from equation. The drag coefficient is a measure adimensional that describes the amount of aerodynamic drag caused by fluid flow, used in the drag equation. Two objects of the same frontal area moving at the same speed through a fluid experience a drag proportional to its Cd. In general, Cd is not an absolute constant for a given body shape. It varies with the speed of airflow (or more generally with Reynolds number). A smooth sphere, for example, has a Cd that varies from high values for laminar flow to 0.47 for turbulent flow. A dimensionless number used in aerodynamics to describe the drag of a shape. The drag coefficient, Cd, is independent of the size of the object and is usually determined in a wind tunnel.

The lift generates by an airfoil, and by extension, the wings will depend on the altitude and speed aircraft, and the lift coefficient which has our airfoil. There are two different ways to increase the lift: increasing the angle of attack or speed.

INTRODUCTION

Increase the angle of attack causes an increase in the Cl, but this has a limit, as speed increases, and that from a certain angle, or velocity, the air starts to come off the wing.

D = ½ ρ V² S Cd

INTRODUCTION

Vortices form because of the difference in pressure between the upper and lower surfaces of a wing that is operating at a positive lift. Since pressure is a continuous function, the pressures must become equal at the wing tips. The tendency is for particles of air to move from the lower wing surface around the wing tip to the upper surface (from the region of high pressure to the region of low pressure) so that the pressure becomes equal above and below the wing. In addition, there exists the oncoming free-stream flow of air approaching the wing. If these two movements of air are combined, there is an inclined inward flow of air on the upper wing surface and an inclined outward flow of air on the lower wing surface. The flow is strongest at the wing tips and decreases to zero at the midspan point as evidenced by the flow direction there being parallel to the free-stream direction.

INTRODUCTION

When the air leaves the trailing edge of the wing, the air from the upper surface is inclined to that from the lower surface, and helical paths, or vortices, result. A whole line of vortices trails back from the wing, the vortex being strongest at the tips and decreasing rapidly to zero at midspan. A short distance downstream, the vortices roll up and combine into two distinct cylindrical vortices that constitute the wingtip vortices. The wingtip vortices trail back from the wing tips and they have a tendency to sink and roll toward each other downstream of the wing. Again, eventually the tip vortices dissipate, their energy being transformed by viscosity.

GEOMETRY

GEOMETRY

GEOMETRY

MESHING

MESHING

MESHING

MESHING

MESHING

MESHING

ANALYSISMach No=0.09

ANALYSIS

ANALYSIS

ANALYSISAOA=8˚

ANALYSIS

ANALYSIS

ANALYSISMach No=0.45

ANALYSIS

ANALYSIS

ANALYSISAOA=8˚

ANALYSIS

ANALYSIS

RESULTS

0 0.2 0.4 0.6 0.8 1 1.20

5

10

15

20

25

30

35

40

4538.33

36.56

20.16

34.56 33.24 33.15

Hybrid wing

M

cl/c

d

RESULTS

0 0.2 0.4 0.6 0.8 1 1.20

5

10

15

20

25

30

3530

21.418.8

15.813.3

11.6

Tailless wing

M

cl/c

d

RESULTS

0 0.2 0.4 0.6 0.8 1 1.28.6

8.8

9

9.2

9.4

9.6

9.8

10

9.62 9.66 9.68

9.11

9.85 9.86

Joined wing

M

cl/c

d

RESULTS

RESULTS

0 0.2 0.4 0.6 0.8 1 1.20

20

40

60

80

100

120

140

160

180

200

21.66

48.21

85.4

112.73

132.12

178.68

Hybrid wing 

M

Vorti

city

RESULTS

0 0.2 0.4 0.6 0.8 1 1.20

0.5

1

1.5

2

2.5

3

0.280.52

1.25

1.52

2.05

2.63

Tailless wing 

M

Vorti

city

RESULTS

0 0.2 0.4 0.6 0.8 1 1.20

10

20

30

40

50

60

70

5.18

11.95

22.53

31.48

41.52

60.25

Joined wing 

M

VOrti

city

RESULTS

Hybrid wing

RESULTS

Tailless wing

RESULTS

Joined wing

CONCLUSION The hybrid wing has lift to drag ratio is much higher than other two wings which are tailless wing and

joined wing, so its aerodynamic efficiency is much higher than two other wing configuration. In hybrid wing L/D gradually decreases with increase in angle of attack similarly in tailless wing L/D nearest to constant value and last one joined wing drastically down ratio after eight degree angle of attack.

Vortices produces with increase in Mach number which are maximum in hybrid wing then after joined wing and last one is tailless wing which has minimum number of vortices generated. In joined wing constant ratio of vortices with respect to Mach number other than two similarly but quite ratio change. The minimum ratio of vortices which is for tailless wing configuration.

By analysis stalling angle as per results first one stall joined wing and then hybrid wing at 12 degree respectively where as in tailless wing stall angle capability little higher than other two wing configuration.

As per overall performance like vortices generation lift to drag ratio and stall angle criteria in which we can consider tailless wing is acceptable because of its overall performance is better than other wing configuration.

As per this project we conclude that wing has some advantages with some penalty also acquired so we have to compromise design configuration as per requirement just for example good lift purpose tailless wing suitable as well as stall capability up to high angle of attack.

Thank you